Package Contents

• One Bolt Size Finder Keychain (Regular or XL, depending on selection)

Product Specifications

• Measurements: Regular: Metric (8–25 mm) and SAE (5/16"–1"); XL: Metric (25–50 mm) and SAE (1"–2")
• Dimensions: Regular: 21 cm × 8.5 cm × 5 cm; XL: 33 cm × 13 cm × 6 cm
• Country of Origin: Taiwan

Features of Our Bolt Size Finder Keychains

Never waste time hunting for the right bolt size again. Whether you’re using the Regular version for your keyring or the XL version for your workshop, Olsa Tools Bolt Size Finder Keychains give you instant, precise bolt size identification anywhere.

• Precision bolt sizing on-the-go: Instantly identify bolt heads with accuracy. The Regular covers 8–25 mm (5/16"–1"), while the XL covers 25–50 mm (1"–2").
• Portable power in your pocket: Compact enough for your keyring (Regular) and perfect for the toolbox or jobsite (XL).
• Dual-sided mastery: Both sizes include Metric and SAE scales—flip sides for total measurement versatility.
• Time-saving efficiency: Eliminate trial-and-error socket fitting. Identify bolt or nut sizes in seconds.
• More than just for bolts: Works like pocket-sized calipers to estimate thread, hose, or fitting sizes.
• Durable construction: Built to last and backed by a limited lifetime warranty against manufacturer defects.
• Unparalleled support: Get answers fast from a real human with a 30-minute average response window.
• 90-day return policy: Not satisfied? Return it within 90 days for a full refund—completely risk-free.

What Sizes of Bolts Can These Bolt Size Gauges Measure?

The Olsa Tools Bolt Size Finder Keychains can measure both metric and SAE bolts across a wide range of sizes. The Regular version covers smaller fasteners, while the XL version handles larger hardware up to 50 mm or 2 inches.

Regular Size Finder – Metric Bolt Gauge Chart

Regular Size Finder – SAE Bolt Gauge Chart

XL Size Finder – Metric Bolt Gauge Chart

XL Size Finder – SAE Bolt Gauge Chart

How to Use the Olsa Tools Bolt Size Finder

1. Move the slider to open the gauge.
2. Place the open ends over the bolt head.
3. Slide upward until the ends fit snugly.
4. Read the measurement closest to the slider for the exact size.

Both the Regular and XL versions follow the same simple and accurate process.

How Do I Know What Bolt Size I Need?

When choosing bolts for a project, you need to match the bolt length, diameter, and thread. Here’s how to do it:

• Diameter: Measure the diameter of the hole or threaded opening the bolt will go into. The bolt diameter should match this measurement.
• Length: Measure the thickness of the materials being fastened together, plus any washers and nuts. The bolt should be long enough to fully engage the nut or threaded hole, but not so long that it protrudes excessively.
• Thread pitch: Use a thread gauge to determine the number of threads per inch (for imperial) or the distance between threads (for metric).
• Material thickness: A general rule of thumb is to use a bolt diameter that is 1.5–2.5 times the thickness of the thinner material being fastened.
• Load requirements: Choose thicker and stronger bolts for high torque or heavyweight applications.
• Head style: Choose based on your application needs (hex, socket, etc.).
• Material: Select based on strength requirements and corrosion resistance needed.

Regular vs. XL — Which One Do You Need?

• Regular (8–25 mm / 5/16"–1"): Portable, keychain-ready, and perfect for everyday use.
• XL (25–50 mm / 1"–2"): Larger format ideal for heavy-duty applications and bigger fasteners.